This invention relates to a vane type motor, compressor or pump of the type in which a fluid medium such as liquid or gas is either acted upon or utilized as the drive mechanism for producing useful work. Thus when utilized as a pump, rotary motion is imparted to the impeller such that the vanes force liquid or gas located within the stator chamber to a point remote thereof. Similarly when used as a compressor, the vanes operate to compress a gaseous fluid similarly present in the stator chamber. Also when operated as a motor, a temperature and/or pressure elevated gaseous medium; for instance, steam, may be directed into the stator chamber so as to cause rotation of the rotor by reason of force exerted upon the vanes from which rotary motion may be usefully directed via a power takeoff associated with the rotor. Obviously, steam in such a situation would be condensed and could be utilized in a closed recycling system. The use of the device as a motor, of course, is not however limited to steam or other condensable fluids but can be operated on pressure differentials unrelated to temperature differences. Also the source of temperature differential when utilized may be from any source including solar energy.
Motors, compressors, or pumps of the above general type construction are well known and include those in which vanes are guided for slidable motion within slots provided in an eccentrically displaced rotor such as shown in FIGS. 6 and 7 of the present drawings. Such vane constructions are representative of the prior art and include disposition in recesses disposed radially; i.e., vertical, to the rotor cylinder such as shown in FIG. 6 wherein the centrifugal force developed by the vanes rotating within the rotor will act against and be supported primiarily by the rotor housing and results in a necessarily high frictional force. This force can be to an extent reduced by a tangential disposition of the vane slots such as shown in FIG. 7. The FIG. 7 arrangement reduces centrifugal force of the vanes against the rotor housing but simultaneously increases the torque of the vanes against the rotor slots and this torque or tilting forces the vanes against the slot walls and thus undesirably causes wear at the interface.
Because of these above-indicated disadvantages, it has been proposed to form a slidable double vane unit such as that shown in U.S. Pat. Nos. 2,314,056; and 2,347,944. In such constructions, however, due to the need of the eccentric displacement of the rotor with regard to the stator housing, the housing must be shaped not in the form of a true circular cylinder but in the form of a generated curve formed in accordance with a complex formula and which necessitates expensive and special machining of the stator housing. An example of such type construction is best shown in U.S. Pat. No. 2,347,944 issued May 2, 1944 in which only relatively minor sections of the rotor housing is formed in a true circular path. Although such constructions are expensive and complex to produce, they do substantially reduce the frictional force at which the vanes contact the rotor housing.
Other ways of increasing the efficiency of such devices by reducing frictional contact of the vanes against the rotor housing have been proposed such as supporting the vanes by means of rollers attached thereto and guided by stationary inner race tracks attached to the stator walls. Such systems have been proposed with differenct stator configuration; for example, as single-action (FIGS. 6-7) or double-acting pump or motor. The attendant disadvantage on all these systems is, however, that the rollers are required to rotate at a much higher RPM than the rotor, approximately 6 to 12 times faster dependent upon the ratio between the O.D. of the roller and the I.D. of the race track.
Thus although the sliding friction of the vanes against the stator housing is eliminated and transferred into rolling resistance of the roller against the stationary inner race track, the attendant very high revolution of the rollers already by moderate rotation of the rotor (approximately 1000 to 2000 RPM) and the necessary additional rotation of the rollers with the rotor around its axis, presents extreme difficult running conditions which requires either substantial speed reduction (rotor RPM) or bearing life time, and thus not acceptable. Therefore this type of systems is limited in its applicability.
It is accordingly the principal objective of the present invention to provide a motor of the aforementioned sliding vane type which effectively reduces the centrifugal force developed by the rotating vanes and which also prevents any remaining centrifugal force from acting against the stator housing in a new, unique, simple, efficient, and effective manner.
This and other features of the present invention are accomodated by the use of a stator housing including a pair of opposed true circular cylinder halves each of which is shortened by a distance equal to about half the internal diameter of a theoretical true cylinder and the horizontal cylinder chord length at the central axis of the rotor. Further improvement of the operating characteristics of the subject motor are provided by incorporation of rollers or sliding shoes attached to the double vanes which in turn roll or slide against idling race rings mounted inside of the hollow rotor and supported by means of a stationary crankshaft.
Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings.